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Siemens
Heating and D.h.w. Controller RVL481
CE1P2541en
Building Technologies
25 Function block "Service functions and general settings"
20.05.2008
Critical locking signals are generated by the boiler temperature controller during protec-
tive boiler startup and during minimum limitation of the boiler return temperature. If the
boiler temperature controller is located in segment 0, the critical locking signal will be
sent to all loads and heat exchangers in the bus network and – if present – to its own
heating and d.h.w. circuit. If the boiler temperature controller is in segment 1…14, it will
deliver the critical locking signal only to all loads in the same segment and – if present –
to its own heating and d.h.w. circuit.
Minimum limitation of the return temperature can also be provided locally by a controller
with plant type no. 1–x. In that case, the critical locking signal only acts inside the con-
troller and is only delivered to the own heating and d.h.w. circuit. With regard to the
response of the consumers and heat converters, there are two choices:
•
Heat converters and consumers with mixing valves:
The flow temperature setpoint will be reduced as a function of the set locking signal
gain. Heat exchanger and load close their mixing valve.
•
Consumers with pump circuit:
When a defined value of the critical locking signal is reached, the pump will be deacti-
vated, independent of the set locking signal gain In plants with changeover valve, the
valve assumes the "Heating circuit” position
25.5 Entries for LPB
25.5.1 Source of time of day
Depending on the master clock, different sources for the time of day can be used. The
source must be entered on the RVL481, on operating line 178, using setting 0…3:
0 = autonomous clock in the RVL481
1 = time of day from the bus; clock (slave) with no remote readjustment
2 = time of day from the bus; clock (slave) with remote readjustment
3 = time of day from the bus; central clock (master)
The effect of the individual entries is as follows:
Input Effect
Diagram
0
•
The time of day on the controller can be
readjusted
•
The controller's time of day is not matched
to the system time
Controller time
System time
Adjustment
1
•
The time of day on the controller cannot be
readjusted
•
The controller's time of day is automatically
and continually matched to the system time
System time
Adjustment
Controller time
2
•
The time of day on the controller can be
readjusted and, at the same time, readjusts
the system time since the change is
adopted by the master
•
The controller's time of day is nevertheless
automatically and continually matched to
the system time
System time
Adjustment
Controller time
3
•
The time of day on the controller can be
readjusted and, at the same time, readjusts
the system time
•
The controller time is used as a pre-setting
for the system
2524
B1
2e
System time
Adjustment
Controller time
In each system, only one controller may be used as a master. If several controllers are
set as masters, a fault status signal will be delivered (error code 100).
Critical locking signals
